Analysis of crystals of retrograded starch with sharp X-ray diffraction peaks made by recrystallization of amylose and amylopectin

Abstract

Retrogradation is a common occurrence of starchy food and many methods have been tried to retard it. Uncovering the crystalline structure of retrograded starch provides us the necessary information to get an effective method. In this paper, the crystals of retrograded sweet potato starch with sharp X-ray diffraction peaks were obtained by blending sweet potato amylose and amylopectin with narrow distribution of molecular weight. The 2θ angles of those crystals were at 14.7°, 20.7°, 24.3°, 26.5°, and 29.9°. Intervals between two branched chains in retrograded amylose were 0.606, 0.348 nm, and in retrograded amylopectin 0.336 nm. A possible mechanism for the formation of those crystals was proposed based on analyzing 1 H NMR, 13 C NMR, X-ray diffraction, and differential scanning calorimeter of those samples. Cocrystallized amylose and amylopectin was necessary to prepare crystals of retrograded starch. More ordered arrangements exist in retrograded starch of sweet potato amylose and amylopectin.ARTICLE HISTORY

Effect of Crystalline and Double Helical Structures on the Resistant Fraction of Autoclaved Corn Starch with Different Amylose Content

“…Moreover, in HS the double helical order of the modified starches, including the order of double helices located inside of the crystallites and those located out-side of the crystalline register, [19,27] affected its resistance to enzymatic digestion. The higher RS contents of autoclaved HS (Table 1) are congruent with the widely accepted idea that amylose is the main molecular component of RS obtained during the reorganization of gelatinized starch; [4] however, since amylose can cocrystallize with amylopectin, [26] the contribution of amylopectin to the RS formation needs to be further studied, especially considering the structural complexity of autoclaved starch systems.…”

“…[ 25 ] During storage of gelatinized starch, amylose, and amylopectin associations occur, involving a recrystallization process. [ 26 ]…”

“…[25] During storage of gelatinized starch, amylose, and amylopectin associations occur, involving a recrystallization process. [26] The autoclaving treatment reduced the ΔH in NS, reflecting a lower degree of structural order in modified starches, [11,21] while in HS a similar behavior was observed, except at 135°C, probably because of the formation of a highly ordered structural matrix, taking into consideration the amount of double helices and their compaction (Table 2-3.5174 in DD and 1.3735 in DO), and the extent of the crystalline regions (Figure 2-19.98% in RC). Because of these trends in our results, ΔH can be used as an indicator of starch ordered structure.…”

Rheological Analysis of the Structuralisation Kinetics of Starch Gels

“…Already, the results of the first roentgenographic investigations [3] have revealed that one of the effects of starch structure changes during the retrogradation process is its partial crystallisation. Further studies carried out using both roentgenographic [18,19], NMR [20,21], as well as calorimetric [22,23] methods confirmed this opinion and created foundations for the quantitative characterisation of the retrogradation process on the basis of the phenomenological theory of crystallisation [24]. However, the performed rheological investigations [25][26][27] indicate that despite a certain correlation with changes in the degree of starch system crystallisation, it is the dispersive structure of amorphous regions that decides the mechanical properties of these systems that have important practical significance.…”

Effects of Spray-Drying Inlet Temperature on the Production of High-Quality Native Rice Starch

“…Waxy rice starch generally possesses an A-type crystalline structure, formed via the interaction of amylopectin with short branch-chains and closed branching points [32]. As such, a XRD spectroscopic analysis of rice starches would often show the characteristic diffraction patterns as defined by peaks at 15°, 17°, 18°, 23° and 26° [33].…”